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What is Mechanical Extract Ventilation (MEV)

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What is Mechanical Extract Ventilation (MEV)

By EnviroVent Feb 22, 2021

A Mechanical Extract Ventilation (MEV) System works in the opposite way to a Positive Input Ventilation System (PIV).  Rather than relying on the introduction of air into the house through a central unit, MEV works by drawing air from multiple rooms such as bathrooms, and other wet rooms such as kitchens and en-suites through a central fan system and then pumping it out of the building, allowing fresh, clean air to be brought into the building from outside in order to replace it.

When a Mechanical Extract Ventilation (MEV) system is installed in a room that is prone to high humidity – such as a bathroom – it works similarly to an extractor fan, pulling the moist air out so that it can be replaced by dry air from elsewhere in the building.  This means that the moist air does not travel into the rest of the building where it can form condensation that would eventually lead to damp problems.

MEV systems run constantly and use little energy.  The systems include humidity sensors which mean that they can adjust the amount of airflow automatically to make them more effective.  A major advantage of MEV over a conventional extractor fan is that due to the fan system being mounted outside the room where the ventilation is needed, they are less intrusive and produce less sound.

Installing an MEV System

Mechanical Extract VentilationMEV Systems need to be installed by a professional.  The installation process is more complex than with a PIV system as holes will need to be cut into brickwork to allow for the intake and outflow of air from the system.  Often, MEV systems are installed as part of a bigger refurbishment project or as part of a new build rather than being retrofitted to an existing building.

The central unit is normally mounted in the loft with ducting installed inside walls and roof spaces to allow for air to flow.  For safety reasons, a professional will be needed to connect the system to the mains electricity.

Benefits of MEV Systems

The primary benefit of an MEV system is its ability to remove moist and humid air directly from the room where it is generated rather than pulling it through the rest of the building.  MEV systems are highly effective at reducing condensation levels throughout the house.

As with all ventilation, MEV systems improve air quality by reducing the amount of dust particles and contaminants that can build up in a property and allow for stale internal air to be constantly replaced with fresh clean air from outside.

MEV systems are highly efficient and require little to no maintenance.  EnviroVent offer a guarantee on their MEV systems and a full installation service through our network of local specialists meaning that you benefit from a system that you can essentially “fit and forget”.

If you are considering a major renovation to your existing property, or in the process of planning a new home, Mechanical Extract Ventilation should be considered thanks to the benefits to the building fabric and air quality that it offers.  For more information, you can arrange a free survey with one of our local specialists who can provide advice and help you with specifying a suitable system for your needs.

Need help with condensation, mould or damp problems?

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One of our local experts will contact you to learn more about your problems, offer free expert advice and make recommendations for a permanent solution.

During the free survey we will:

  • Assess any condensation, damp or mould problems in your property
  • Take readings of the relative humidity levels
  • Identify any underlying problems and make recommendations for a permanent solution